What is the subject and is this sentence correct?

The flock are flying south for the winter

explanation:

i don t know the answer but i need points but i think is for the most important day to my teacher

The details that best show evidence of tribal traditions are, "never in the history of his people had a man married a woman who spoke a different tongue” and "it has never been heard," was the verdict of an old man speaking a few weeks later.